Telephone-transmitter.



No. 739,208. PATBNTED SEPT. 15, 1903. D. OBRIEN.

TELEPHONE TRANSMITTER.

APPLICATION FILED 811M. 6. 19oz.

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UNITED STATES Patented. September 15, 1903.;

DENNIS OBRlEN, OF LIMESTONE, NEW YORK.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 739,208,dated September 15, 1903. Application filed September 6, 1902. Serial No. 122,351. (No model.)

To all whom it may concern:

Be it known that I, DENNIS OBRIEN, a citizen of the United States, and a resident of Limestone, in the county of Catt-araugus and State of New York, have invented a new and Improved Telephone-Transmitter, of which the following is a full, clear, and exact description.

My invention relates to telephone -transmitters, my principal object being to increase the loudness of the sounds while maintaining the purity thereof.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in both views.

Figure 1 is a central section on the line 1 1 in Fig. 2 of a transmitter embodying my invention; and Fig. 2 is a front elevation of one of the transmitters in its normal position, certain parts being removed for the sake of clearness.

The base 1 of insulating material is provided with an annular shoulder 2 and with a flat cylindrical wall or edge 3, thus constituting a cup-like cavity. Stretched over the member 3 is an elastic membrane or diaphragm 4, which is made, preferably, of nonconducting material and which is extensible when subjected to tension. I find soft rubber to be an appropriate material for making this membrane. The circumferential edge of the diaphragm is secured to a ring 5, and this ring being enveloped in the membrane, as in? dicated, is engaged by an annular shoulder 6, integral with the mouthpiece 7. This annular shoulder 6 is engaged by screw-bolts 8, which pass loosely through the base 1 and are provided with thumbnuts 9, as indicated in Fig.

1. By tightening or loosening the thumbnuts the ring 5 is drawn toward the base 1 or allowed to recede therefrom, thus tensioning the membrane l Mounted centrally upon the membrane d is a light thin disk 10 of iron, which may, if desired, be cut from a sheet of tintype iron. A lever 11, made, preferably, of non-magnetic material, is provided with a point 12, which is made, preferably, of iron. The lever 11 is pivoted at 13 upon a cross-pin l4 and is fulcrumed upon a short needle 15, quite analogous to an ordinary sewing-needle, but shorter than the same, and through the eye of which the lever 11 passes. This needle 15 loosely engages an adjustable screw 16, upon the end of which a funnelshaped bearing is provided. The screw 16 passes through a plate 18, provided with a set-screw 19, for the purpose of retaining the screw 16 in any predetermined position. The screw 16, the needle 15, and the lever 1.1 are heated to a high degree of heat and allowed to cool in atmospheric air for the purpose of oxidizing them slightly. The object of this step is to provide each of them with a superficial layer of semiconducting oxid for the purpose of producing an imperfect contactbetween them. In other words, the parts are oxidized for the purpose of giving them a microphonic property.

A plate 20 is sunken into the base 1, as indicated in Fig. 1, for the purpose of supporting an induction-coil. This coil consists of a secondary winding 21, a primary winding 22, and an iron core 23, this core having the general form of a screw engaging the plate 20, as indicated in Fig. 1. By rotating the screw or core 28 it is adjusted relatively to the iron disk 10, which serves as an armature and through the agency of which the vibrations of the diaphragm 4: may be effected magnetically. A battery 24 is connected by wires 25 with the primary winding 22 and also with the screw 16, lever 11, and needle 15, as indicated more particularly in Fig. 1. The line-wires are shown at 27 28, the receiver 29 being connected therewith.

The general operation of my device is as follows: Current from the battery 24 passes through the wires 25, the imperfect contact made by the lever 11, needle 15, and bearing 17 to the primary winding 22. If now sounds are produced adjacent to the mouthpiece 7, the diaphragm 4 and the armature 10 will be caused to vibrate. An undulatory current passes through the primary winding 22,ther.eby energizing the core 23, causing the same to attract the armature 10 with avariable de- 'gree of power, each variation being proportionate to the intensity of the current passing through the imperfect contacts. By this augment the amplitude of the mechanical vibrations of the diaphragm 4. The attraction of the core 23 for the armature 10 is great or little according to the amplitude of motion of the diaphragm 4 as acted upon mechanically by the voice. The result is that the magnetic action of the core 23 is simultaneous with what would otherwise be the undisturbed mechanical action of the diaphragm 4. The pressure upon the imperfect contacts therefore is greatly augmented, so that the amount of current actually passing through the wires 25 26 varies within much wider limits than would be the casein the absence of the magnetic action described. The primary winding 22 being thus powerfully aifected induces still more powerful currents in the secondary winding 21, this action being the same as in telephones heretofore used. The result is that the electric undulations passed out upon the line-wires 27 28 are very much more powerful than would otherwise be the case.

It will be noted that by adjusting the thumbnuts 9 and thereby tensioning the diaphragm 4 there is no disturbance of the position occupied by any of the members forming the imperfect contact above described. To increase the tension of the diaphragm i does not in any way affect the tension of the imperfect contact.

It will be noted that my apparatus has some of the functions of a relay and a repeater in that it reinforces the strength of an undulatory current. I do not limit my invention, therefore, to use as a transmitter, as it may be used for any other purpose.

Having thus described my invention, I claim as new and desire to secure by Letters .Patent 1. A telephone-transmitter, comprising a member provided with a cylindrical wall, an extensible diaphragm engaging said wall and provided with a marginal ring encircling the same, means for adjusting said ring relatively to said wall for the purpose of tensioning said diaphragm, contact connected with said diaphragm, and electrical conductors connected with said contact for energizing the line.

2. A telephone-transmitter, comprising a base, a diaphragm mounted thereon, a lever of conducting material connected with said diaphragm and actuated thereby, a needle mounted upon said lever, a screw mounted within said casing and forming an imperfect electrical contact with said needle, and a source of electricity connected with said screw and with said needle.

diaphragm, a needle in electrical communication with said lever, an adjustable member connected with said needle and forming an imperfect contact therewith, and a magnet provided with primary and secondary windings and with electrical connections, said magnet being disposed adjacent to said armature and free to actuate the same.

4. In a telephone-transmitter, a vibratory diaphragm, a lever of conducting material connected with said diaphragm and movable thereby, a needle in electrical communication with said lever, and an adjustable member connected with said lever and forming an imperfect contact therewith.

5. In a telephone transmitter, a magnet provided with primary and secondary windings and with electrical connections, a vibratory diaphragm disposed adjacent to said magnet and provided with an armature therefor, a lever connected with said armature, and an imperfect contact connected with said lever and with said primary winding.

6. In a telephone-transmitter, a magnet provided with primary and secondary windings and with electrical connections, a vibratory diaphragm disposed adjacent to said magnet and provided with an armature therefor, a lever connected with said armature, an imperfect contact connected with said lever and with said primary winding, and means for adjusting said imperfect contact.

7. In a telephone -transmitter, a magnet provided with primary and secondary windings and with electrical connections, a vibratory diaphragm disposed adjacent to said magnet and provided with an armature therefor, a lever connected with said armature, an imperfect contact connected with said lever and with said primary winding, means for adjusting said imperfect contact, and mechanism, controllable at will, for tensioning said diaphragm.

8. In a telephone-transmitter, a magnet provided with primary and secondary windings and with electrical connections, a vibratory diaphragm disposed adjacent to said magnet and provided with an armature therefor, a lever connected with said armature, an imperfect contact connected With said lever and with said primary winding, means for adjusting said imperfect contact, and mechanism for tensioning said diaphragm independently of said imperfect contact.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

DENNIS OBRIEN.

Vitnesses:

W. H. PERRAM, THEODOR REIBENSTEIN. 

